Peanut allergen quantification: a tough nut to crack

As part of the National Measurement Laboratory’s 30th anniversary, we’re sharing stories and case studies from the last three decades.

One of our case studies touches on an issue that affects hundreds of thousands of people across the UK alone: peanut allergies. So read on to learn how LGC scientists developed a unique allergen quality control material, which can be used to help protect the people in the UK with a peanut allergy and also help to prevent contamination in the food production process, potentially saving the food industry millions of pounds.

The problem

The prevalence of peanut allergy has nearly doubled in Europe over the past two decades and it now affects around 500,000 people in the UK [1]. Peanut allergy is the most common cause of fatal food allergy reaction. It occurs when the immune system mistakenly identifies peanut proteins as something harmful. The fear of accidental exposure in food reduces the quality of life of peanut allergy sufferers and severely limits the social habits of allergic individuals, their families and even their friends.

SMALL_iStock_000004018390Small peanutsIt is not only those with peanut allergies who have to worry about the risk of allergic reactions or death by anaphylaxis; it also creates problems for businesses. Testing for allergen proteins in food is difficult, as samples usually contain a lot of protein and it can be difficult to separate the allergen protein of interest. This has an impact on the ability of manufacturers and suppliers to adequately label their goods and also has implications for defining threshold levels and detecting food fraud.

All food companies throughout the EU are compelled by law to declare major allergens including peanut, if included in food products as ingredients. The current labelling rules, brought into force in December 2014 by European Regulation 1169/2011 (the EU Food Information for Consumers Regulation, EU FIC) ensure that all consumers are given highlighted information about the use of allergenic ingredients in pre-packed food [2]. This is to make it easier for people with food allergies to identify the foods they need to avoid. The EU FIC also extends to food sold loose or served when eating out. Prevention of cross contamination with peanut through product testing, validation and verification of cleaning, and checking of ‘peanut-free’ products requires exacting testing.

ELISA (enzyme-linked immunosorbent assay), PCR (polymerase chain reaction) and mass spectrometry (MS) methods can be used to detect food allergens, but there are problems obtaining reliable quantitative results with all three. Prior to this project, there were no suitable reference materials available in the form of a food matrix, making it difficult for laboratories and test-kit manufacturers to validate quantitative methods for allergen measurement.

The solution

A quality control (QC) material that is a real food, containing a known amount of specific allergen protein, and is stable and homogenous could assist laboratories in the validation and monitoring of their analysis. Consequently, a project was undertaken by LGC to develop a food matrix peanut allergen QC material.

The chosen matrix was a chocolate dessert product developed for low-dose threshold studies in food allergic individuals in the European research project ‘EuroPrevall’. Two QC materials were prepared by University of Manchester researchers in the form of chocolate dessert product pastes designed to be reconstituted with water before analysis. One material (LGCQC1011) was prepared as a peanut free negative control and the other material (LGCQC1012) was prepared as a positive control with the addition of light roast, partially defatted peanut flour (a commercial food ingredient) to give a peanut protein content of 10 mg kg-1. The pastes were transferred to LGC, packaged in nitrogen-flushed sealed sachets to aid stability and the units were numbered sequentially in fill order. LGC assessed and proved their homogeneity and stability, underpinned by a validation study of the test method using a commercially available ELISA kit (Romer AgraQuant® Peanut kit). The National Measurement System funded the ELISA kit validation studies, and a Technology Strategy Board and LGC co-funded research and development project established the design and production of the QC material.

Impact

Failure in food allergen management means ‘food-allergen’ related incidents are the most common reason for product withdrawals and recalls in the United Kingdom according to the UK Food Standards Agency. The 34 recalls related to allergens in 2010 were estimated to cost stakeholders £10- 15 million. In 2013, the number of Allergy Alerts issued to withdraw food or drink products had risen to 47.

Phil Goodwin, MD of Bio-Check (UK) a food allergen test kit manufacturer, has worked in this area for 30 years and welcomes LGC’s recent initiatives:

“The science of food allergen detection, let alone quantitation, has failed to move forward anything like quickly enough since it began in the late 1980s. The emergence of such high quality QC materials as are being produced by LGC is a significant step forward to a time when all commercial test kits can be demonstrated to show good agreement on allergen levels. LGC are to be applauded for taking on this difficult challenge and I urge all allergen kit producers and analysts to use the material to improve their products and results.”

 

[1] http://www.mrc.ac.uk/news-events/publications/outputs-outcomesand-impact-of-mrc-research-2013-14/

[2] http://allergytraining.food.gov.uk/english/rules-and-legislation/

This blog first appeared as a NML case study on the LGC Group website. To learn more about the NML, visit their site here.

Food Safety Week and beyond: LGC’s long history in food testing

Food Safety Week, organised by the UK’s Food Standards Agency, is an opportunity to learn more about current food issues, including food crime, compliance and food hygiene. This year’s campaign celebrates “the people who protect your plate” – the workers who ensure the UK public can trust the food they eat, including inspectors, local authorities, and public analysts.

Also at the forefront of the fight for food safety are chemists, who analyse food, drinks and supplements to ensure manufacturers can verify the safety of their food products.

tea_world food day

The original Government Laboratory plaque and tea samples.

Consumers trust that when they buy food and drink, they are getting exactly what they’ve been told they are getting.  Each food has a distinct composition, much like its own fingerprint, and with the right expertise and tools, it’s possible to study these foods to determine their authenticity.  LGC has been involved in food testing for over 175 years. In fact, it’s the very reason we were established. In 1842, the Board of Excise needed a scientific authority to see that goods, like tea, tobacco and spirits, were not adulterated for profit, and so it created the Government Laboratory.

The Government Chemist role was created in 1909, to ensure the Laboratory of the Government Chemist could work independently of the Inland Revenue department (which provided staff to the Laboratory) and the Board of Customs and Excise (which controlled it). Nowadays the Government Chemist oversees the statutory function of referee analyst, resolving disputes over analytical measurements, particularly in relation to food regulatory enforcement.

As LGC grew, so did our roles involved in food and feed testing. Not only are we involved as the referee analyst for disputes in the food industry, we also provide products and solutions to food safety-related issues.

In order for food producers to know with certainty that their food is authentic, it’s necessary to compare what they’ve produced with a known and verified version of the food – this is called a reference material, or standard.  Currently, we have over 15,000 reference materials for food analysis, for everything from allergens, contaminants, and toxins to food flavourings, dyes and proteins, and much more.

Chemists also study new methods of authenticating foods, including via mass spectrometry, which is considered to be the gold standard in analysis, especially when combined with chromatography. Mass spectrometers analyse a sample’s elemental molecular weight, which is its ‘fingerprint’.  The tools and expertise of the National Measurement Laboratory at LGC allow our measurement scientists to be accurate about the content of a sample to up to one part per quadrillion. In other words, we can detect one lump of sugar dissolved in a bay.  These capabilities allow us to work on specific projects, tailoring our research to benefit many different sectors and solve specific problems.

This was particularly evident during a recent case studying selenium within food products and supplements.  It is essential that the correct amount and species of selenium is present in order for fortified food products and supplements to be safe for human consumption.  Selenium-enriched foods and supplements have become more prominent in Europe since it has moved to using more wheat that is naturally low in selenium.

However the accurate measurement of total selenium in food and food supplements presents analytical challenges due to the complex nature of food samples. Furthermore, selenium speciation analysis presents additional challenges due to the low levels of each specific selenium species and the molecular complexity of such samples.

LGC’s measurement research team for inorganic mass spectrometry has extensive experience in selenium speciation and was able to develop and characterise a range of reference materials, including a matrix selenium-enriched wheat flour standard, to support the food industry.

With over 175 years in the food testing arena, we have a lot to say about the subject, so if you want to learn more, head over to our website where you can read case studies and learn about our reference materials.

You can also join us at next week’s Government Chemist Conference, where we will be discussing current food safety issues at length, including Brexit, food authenticity, and food regulation, with many experts in their fields, including the FSA themselves. Visit the conference website to view the entire programme and register.